HMRC thinks you've been overpaid but you can prove you were paid the right amount

HMRC want you to repay an overpayment - but the overpayment wasn't your fault

You have 1 month from the date of the decision to ask for mandatory reconsideration. You'll find the date at the top of your decision letter. You can still ask for a reconsideration after the deadline, but you'll need a good reason - for example, because you'd spent some time in hospital.

Check you have evidence

HMRC will usually only change a decision if you have evidence to prove it was wrong.

For example:

bank statements or receipts to prove you spend enough money on your child's needs if they don't live with you

payslips that show you're working in this country - if you're an EEA national and need to show you've a right to reside

evidence from your child's school or doctors that shows your address as the child's address

travel tickets that show you weren't away from the country for more than 8 weeks

a letter from your child's school or college to show they are still in full-time education

Proving you reported a change in circumstance

HMRC might have stopped your benefit or think you've been overpaid if they missed a change you reported.

If you reported the change through your Government Gateway account, you could send HMRC a screenshot or print out of the reported change - it should still be visible in your account.

If you wrote to HMRC to report the change, send copies of the letter and proof of postage, if you have it.

If you called HMRC to report the change, you can ask for an audio or written copy of the call on GOV.UK. This is called a 'subject access request'. It can take 6 to 8 weeks for a subject access request to come through, so don't wait for it. Send the letter asking for the mandatory reconsideration and say that you've made a subject access request and will send the evidence when you have it.

If it's taking time to get your evidence together, don't delay sending your mandatory reconsideration. Send any evidence you find later and get proof of postage.

Write to HMRC

It's best to send a letter to HMRC to ask for a mandatory reconsideration so you have everything in writing.

In your letter, explain why you disagree with their decision and give facts and examples to support your reasons.

If your decision letter from HMRC includes the reasons for their decision, make it clear in your letter which ones you disagree with and why. If your decision letter doesn't include a statement of reasons, call HMRC and ask for a 'written statement of reasons' - you'll get more time for your mandatory reconsideration.

Add your phone number, email or address so that HMRC can contact you if they have any questions. Explain if you'll have any problems getting to the phone, for example because it's difficult for you to move around.

Send your letter to the address on your Child Benefit decision letter. It's a good idea to get proof of postage in case you need it later.

If the 1-month deadline is near or has passed

If it's just a few days until the 1-month deadline, you should call HMRC and ask for the mandatory reconsideration over the phone. Make a note of the date and time you call, the name of the person you spoke to and what you told them.

Calls cost up to 40p a minute from mobiles and up to 9p a minute from landlines. It should be free if you call from your mobile and have landline calls included in your contract.

If you've missed the 1-month deadline

You can still ask for a mandatory reconsideration, as long as it's within 13 months of the decision.

You'll need to give a good reason why you couldn't ask within 1 month. For example, because you'd spent some time in hospital.

When you write your letter to HMRC, include the reasons why you missed the 1-month deadline.

If you got the decision letter more than 13 months ago

HMRC might change the decision if they made a mistake – known as an 'official error'. For example, if they wrongly recorded your change of circumstance.

You'll need to write to HMRC to explain why you think they made an official error - send your letter to the address on the decision letter. Write 'Request for official error revision' at the top of your letter and include:

Getting your mandatory reconsideration decision

HMRC will contact you if they need more information or evidence.

You'll usually need to send any further evidence within 1 month of the date of the phone call or letter. If it will be hard for you to do this, you should tell HMRC when they contact you. They might then extend the deadline.

You'll be sent a 'mandatory reconsideration notice' when HMRC has looked at your claim and made a new decision. This letter will explain what they've decided and why.

You might have to wait about 3 weeks before you get your letter - if it hasn't arrived after 1 month, call HMRC to check it's being looked at. You can make a complaint if it's taking months to come through.

If HMRC changes their decision, your payments will be backdated to the date your Child Benefit was stopped.

Extra help you can get while you're waiting for mandatory reconsideration

You might be able to get other help with your living costs while you're waiting for your Child Benefit decision - for example to help pay for food or school costs. Check what help you can get.